Inhaler

ABSTRACT

An inhaler comprising a housing defining a chamber to receive a strip having a plurality of blisters each containing a dose of medicament for inhalation by a user is disclosed. It comprises an inhaler comprising a housing to receive a strip having a plurality of blisters, each blister having a puncturable lid and containing a dose of medicament for inhalation by a user, a mouthpiece mounted to the housing and through which a dose of medicament is inhaled by a user, a blister piercing member mounted for rotation about a first axis and an actuating mechanism including an actuating lever mounted for rotation about a second axis to sequentially move each blister into alignment with the blister piercing member, wherein the actuating lever co-operates with the blister piercing member so that the blister piercing member pivots about said first axis in response to rotation of the actuating member from an initial position about the second axis to puncture the lid of an aligned blister so an airflow through the blister is generated to en-train the dose contained therein and carry it, via the mouth-piece, into the users airway when a user inhales through the mouthpiece. The inhaler comprises an actuating lever load control member to control the force that must be applied to the actuating lever to cause it to rotate from its initial position such that a biasing force is applied to the actuating lever throughout all, or at least a substantial portion of, the stroke of the actuating lever.

This application is a national phase application under 35 U.S.C. § 371of International Application No. PCT/GB2013/051261, filed May 16, 2013,which claims priority to GB 1209267.2, filed on May 25, 2012, thedisclosures of which are all hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to an inhalation device for oral or nasaldelivery of medicament in powdered form. More specifically, theinvention relates to an inhaler having a housing to receive a striphaving a plurality of blisters spaced along the length of the strip,each blister having a puncturable lid and containing a dose ofmedicament for inhalation by a user. The invention also relates to aninhaler containing a strip of blisters each having a puncturable lid andcontaining a dose of medicament for inhalation by a user of the deviceaccording to the invention.

BACKGROUND

Oral or nasal delivery of a medicament using an inhalation device is aparticularly attractive method of drug administration as these devicesare relatively easy for a patient to use discreetly and in public. Aswell as delivering medicament to treat local diseases of the airway andother respiratory problems, they have more recently also been used todeliver drugs to the bloodstream via the lungs, thereby avoiding theneed for hypodermic injections.

It is common for dry powder formulations to be pre-packaged inindividual doses, usually in the form of capsules or blisters which eachcontain a single dose of the powder which has been accurately andconsistently measured. A blister is generally cold formed from a ductilefoil laminate or a plastics material and includes a puncturable lidwhich is permanently heat-sealed around the periphery of the blisterduring manufacture and after the dose has been introduced into theblister. A foil blister is preferred over capsules as each dose isprotected from the ingress of water and penetration of gases such asoxygen in addition to being shielded from light and UV radiation all ofwhich can have a detrimental effect on the delivery characteristics ofthe inhaler if a dose becomes exposed to them. Therefore, a blisteroffers excellent environmental protection to each individual drug dose.

Inhalation devices that receive a blister pack comprising a number ofblisters each of which contain a pre-metered and individually packageddose of the drug to be delivered are known. Actuation of the devicecauses a mechanism to breach or rupture a blister, such as by puncturingit or peeling the lid off, so that when the patient inhales, air isdrawn through the blister entraining the dose therein that is thencarried out of the blister through the device and via the patient'sairway down into the lungs. Pressurized air or gas or other propellantsmay also be used to carry the dose out of the blister. Alternatively,the mechanism that punctures or opens the blister may push or eject thedose out of the blister into a receptacle from which the dose maysubsequently be inhaled.

It is advantageous for the inhaler to be capable of holding a number ofdoses to enable it to be used repeatedly over a period of time withoutthe requirement to open and/or insert a blister into the device eachtime it is used. Therefore, many conventional devices include means forstoring a number of blisters each containing an individual dose ofmedicament. When a dose is to be inhaled, an indexing mechanism moves apreviously emptied blister away from the opening mechanism so that afresh one is moved into a position ready to be opened for inhalation ofits contents.

An inhaler of the type described above is known from the Applicant's ownco-pending international application that has been published asWO2005/037353 A1.

According to one embodiment described and claimed in WO 2005/037353 A1,and illustrated in FIGS. 1 and 2 of the accompanying drawings, aninhaler 1 has a housing 2 containing a coiled strip of blisters 3. Anindexing mechanism 4 comprising a single actuating lever 5 unwinds thecoil 3 one blister at a time so that they pass over a blister locatorchassis 6 and successively through a blister piercing station 7, whenthe actuator 5 is pivoted in a direction indicated by arrow “A” in FIG.2. The blister 3 a located at the blister piercing station 7 on eachmovement of the actuator 5 is pierced on the return stroke of theactuator 5 (in the direction indicated by arrow “B” in FIG. 2) bypiercing elements 8 on the actuator 5 itself so that, when a userinhales through a mouthpiece 9, an airflow is generated within theblister 3 a to entrain the dose contained therein and carry it out ofthe blister 3 a via the mouthpiece 9 and into the user's airway.

The device known from WO02005/037353 A1 has already been modified so asprovide a fully integrated device, i.e. one in which the used blistersare retained within its housing so that a user never has to come intodirect contact with the blister strip. In one modified embodiment, knownfrom the Applicant's own previous application that has now beenpublished as WO09/007352 A1, there is provided a flexible and resilientspiral element mounted within the housing of the device into which theused portion of the blister strip is directed so that, as the strip isgradually used up, the spiral expands as more and more of the strip isfed or pushed into it between its coils. The inhaler of the presentinvention, in its preferred form, is also a fully integrated device thatretains the used blisters, although in a preferred embodiment it has awall to separate the interior of the housing into used and unusedblister compartments. The wall is preferably rigid and slideably mountedso that the size of the unused and used blister compartments changesrelative to each other as the number of blisters that are used increasesand the number of unused blisters decreases.

The aforementioned document also describes an embodiment in which usedblisters are crushed between the blister strip drive or indexing wheeland the inner surface of the casing of the device, which is also afeature of the inhaler of the present invention. As crushing takes placeas the used strip passes around the blister strip drive member, a curlor curved form is imparted to the strip which helps it to coil up withinthe chamber.

The inhaler of the invention may also incorporate a blister strip drivemechanism or indexing mechanism that forms the subject of theApplicant's own previous international application that has nowpublished as WO2009/092652 A1.

The disclosures of WO2005/037353 A1, WO09/007352 A1 and WO2009/092652 A1are all incorporated herein by reference.

The present invention seeks to provide another inhalation device of thetype disclosed in the above-mentioned applications, and which also has arelatively simple construction, is robust, straightforward tomanufacture and easy for the patient to use.

SUMMARY OF THE INVENTION

According to the invention, there is provided an inhaler comprising ahousing to receive a strip having a plurality of blisters, each blisterhaving a puncturable lid and containing a dose of medicament forinhalation by a user, a mouthpiece mounted to the housing and throughwhich a dose of medicament is inhaled by a user, a blister piercingmember mounted for rotation about a first axis and an actuatingmechanism including an actuating lever mounted for rotation about asecond axis to sequentially move each blister into alignment with theblister piercing member, wherein the actuating lever cooperates with theblister piercing member so that the blister piercing member pivots aboutsaid first axis in response to rotation of the actuating member from aninitial position about the second axis to puncture the lid of an alignedblister so an airflow through the blister is generated to entrain thedose contained therein and carry it, via the mouthpiece, into the user'sairway when a user inhales through the mouthpiece, wherein the inhalercomprises an actuating lever load control member to control the forcethat must be applied to the actuating lever to cause it to rotate fromthe initial position such that a biasing force is applied to theactuating lever throughout all, or at least a substantial portion of,the stroke of the actuating lever.

The load control member may comprise a cantilever on the actuating leverand a ramp on the housing, said ramp being shaped to change the degreeof deflection of the cantilever during the stroke of the actuatinglever.

Optionally, the ramp is shaped such that the load applied to thecantilever gradually increases until the blister piercing member beginsto pivot about said first axis.

The ramp may be shaped so that the load applied to the cantilever isgradually released, the force of the cantilever against the ramp urgingthe actuating lever into a fully actuated position.

The blister piercing member may be immovably attached to the mouthpieceand the mouthpiece may be pivotally mounted to the housing so that themouthpiece pivots, together with the blister piercing member, about saidfirst axis in response to rotation of the actuating lever about thesecond axis.

Alternatively, the blister piercing member may be pivotally mounted tothe mouthpiece for rotation about said first axis so that the blisterpiercing member pivots about said first axis relative to the mouthpiece,in response to operation of the actuating lever.

The actuating lever is preferably pivotable in the same direction aboutthe second axis to sequentially move each blister into alignment with ablister piercing member and to cause rotation of the blister piercingmember about the first axis so that the blister piercing memberpunctures the lid of an aligned blister.

Preferably, the actuating mechanism is configured such that rotation ofthe actuating lever about the second axis through a first portion of itsstroke moves a blister into alignment with a blister piercing memberand, further rotation of the actuating lever about the second axis inthe same direction, during a second portion of its stroke, causesrotation of the blister piercing member about the first axis so that theblister piercing member punctures the lid of an aligned blister.

The actuating mechanism may include a blister strip drive wheel, whereinthe actuating lever is engaged with said blister strip drive wheelduring rotation of the actuating lever to rotate said blister stripdrive wheel and drive said strip.

The blister strip drive member may comprise a plurality of spokesextending from a hub, the spokes being spaced from each other such thata spoke locates between blister cavities as a blister strip passesaround the blister strip drive member to engage and drive a strip as theblister strip drive member rotates, the blister strip drive member beingpositioned relative to a wall such that the distance between the hub andsaid wall is less than the height of a blister cavity such that onwardrotation of the wheel causes a blister cavity to be at least partiallysquashed or sandwiched between the hub and said wall.

The actuating mechanism may be configured such that the actuating leverand blister strip drive wheel disengage at the end of the first portionof the stroke so that the blister strip drive wheel remainssubstantially stationary during rotation of the actuating lever throughsaid second portion of its stroke.

The actuating mechanism may comprise a drive coupling member rotatablein response to rotation of the actuating lever to rotate the blisterstrip drive wheel, the blister strip drive wheel being rotatably mountedon said drive coupling member, wherein the actuating mechanism includesmeans to control rotation of the blister strip drive wheel relative torotation of the drive coupling member so that the blister strip drivewheel rotates together with the drive coupling member during the firstportion of the stroke of the actuating lever but not during the secondportion of the stroke of the actuating lever.

Said means for controlling rotation of the blister strip drive wheel mayalso be configured to inhibit rotation of the blister strip drive wheelwhen the actuating lever is rotated in the opposite direction.

In one embodiment, the drive coupling member includes a drive gearrotatable together with the drive coupling member and the actuatinglever includes a drive gear segment that drivingly engages with thedrive gear member so that the drive gear rotates in response to rotationof the actuating lever to rotate the drive coupling member.

The means to control rotation of the blister strip drive wheel mayinclude cooperating elements on the drive coupling member and on thehousing.

One of the actuating lever and the mouthpiece may have a drive camelement and the other of the actuating lever and the mouthpiece may havea drive cam surface, wherein the drive cam element cooperates with thedrive cam surface so that the mouthpiece pivots about said first axis inresponse to rotation of the actuating member about the second axis topuncture the lid of an aligned blister.

The drive cam surface may include a cam groove, the cam groove having anarcuately shaped region having an axis that corresponds to the secondaxis about which the actuating lever rotates such that, during saidinitial rotation of the actuating lever through its first portion of itsstroke, the drive cam element slides along said arcuately shaped regionof the cam groove without causing rotation of the blister piercingmember about the first axis.

The cam groove may have a second region shaped such that, during furtherrotation of the actuating lever through its second portion of itsstroke, cooperation between the drive cam element and the second regionof the cam groove causes the mouthpiece to rotate together with theactuating lever so that the blister piercing element punctures the lidof an aligned blister.

Preferably, the inhaler comprises a cap and a coupling pivotallymounting the cap to the housing for rotation about a third axis, the capcovering the mouthpiece in a closed position.

The housing may comprise a shell and the actuating lever may be mountedfor rotation about the second axis on the shell and optionally includesa mounting plate that extends within a space between the shell and thecap.

The actuating lever may comprise a button extending from said plate andprotruding out of said space to enable actuation of the actuating leverby a user.

The actuating lever may comprise an arcuately shaped opening extendingabout the second axis, the coupling that pivotally mounts the cap to thehousing extending through said opening so that the coupling travelsalong the arcuately shaped opening as the actuating lever pivots aboutthe second axis.

The cap and actuating lever may include cooperating means configuredsuch that, when the cap is rotated from its open position back into itsclosed position in which it covers the mouthpiece, the actuating leveris rotated rotate back into its initial position.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to FIGS. 18a and 18b of the accompanying drawings,in which:

FIGS. 1 and 2 are side views of a conventional inhalation device to showhow a strip is driven to sequentially move blisters into alignment witha blister piercing element by movement of an actuator from the positionshown in FIG. 1 to the position shown in FIG. 2 which drives an indexingwheel. A piercing head on the actuator pierces the lid of an alignedblister when the actuator is returned to its normal position, as shownin FIG. 1;

FIGS. 3a to 3e is a sequence of drawings to show the general functionand operation of an inhaler which does not form part of the inventionbut is described as background information only;

FIG. 4 is a side elevation of an inhalation device that does not formpart of the invention;

FIG. 5 is the side elevation of FIG. 4, but with the cap removed so thatthe internal components can be seen;

FIG. 6 is the side elevation of FIG. 5 after removal of one-half of theshell forming the housing of the inhaler;

FIG. 7 is an exploded perspective view showing the individual componentsof the inhaler;

FIG. 8 is a partial perspective view of the blister strip indexingmechanism;

FIG. 9 is a partial perspective view of the blister strip indexingmechanism shown in FIG. 8 following partial rotation of the actuatinglever into an intermediate position from its home position;

FIG. 10 is the same view as shown in FIG. 9, but without the optionalcantilevered chassis arm;

FIG. 11 is a partial perspective view of the blister strip indexingmechanism shown in FIGS. 8 to 10, after the actuating lever has beenrotated to a point at which drive between the drive coupling and theactuator has disengaged;

FIG. 12 is a partial perspective view of the opposite side of theindexing mechanism shown in FIGS. 9 to 11;

FIG. 13a is a perspective view of the drive coupling used in theindexing mechanism of the inhaler shown in FIGS. 9 to 12;

FIG. 13b is a side view of the drive coupling illustrated in FIG. 13a inwhich the flexible flange portion has been deflected in a direction “T”towards the shaft or, towards an indexing wheel mounted on that shaft;

FIG. 14 is a partial view of the inhaler according to the inventionshowing the form and position of the indexing wheel that may be used inorder to crush used blisters as they pass around the indexing wheel;

FIG. 15 is an exploded perspective view showing the individualcomponents of an inhaler which is included as background informationonly;

FIG. 16 is a cross-sectional side view of the inhaler shown in FIG. 15;

FIGS. 17a to 17f illustrate a further modified embodiment of the inhalerthat incorporates a shutter to block the mouthpiece; and

FIGS. 18a and 18b show an inhaler according to the invention.

DETAILED DESCRIPTION

Referring now to FIGS. 3a to 3e of the accompanying drawings, there isshown an inhaler 10 having a housing 11 formed from two shell portions11 a, 11 b (see FIGS. 6 and 7), a cap 12 pivotally mounted to thehousing 11 for rotation about an axis marked “C” (see FIGS. 5 to 7) froma closed position as shown in FIG. 4 in which the cap 12 covers andprotects a mouthpiece 13 to a fully open position, as shown in FIGS.3(b) to 3(d) and in a direction indicated by arrow “R” in FIG. 3(a), inwhich the mouthpiece 13 is exposed to enable a user to inhale a dose ofmedicament through the mouthpiece 13.

It should be noted that the cap is ‘passive’ in the sense that it can beopened and closed freely without performing the function of indexing ofthe blister strip or causing a blister piercing member 15 depending fromthe mouthpiece 13 to pierce the lid of an aligned blister.

The cap 12 is rotated into its fully open position in the direction ofarrow “R”. An actuating lever 14 is revealed as soon as the cap 12 isrotated out of its closed position. The user then applies pressure tothe actuating lever 14, so that it rotates in the direction indicated byarrow “S” in FIG. 3(b).

During initial rotation of the actuating lever 14 through a firstportion of its stroke into the position as it is shown in FIG. 3(b), thestrip is indexed so as to move an unused blister into alignment with theblister piercing member 15.

When the actuating member is rotated through a second portion of itsstroke beyond the position shown in FIG. 3(b) and after having completedthe first portion of its stroke, in the direction of arrow “T” in FIG.3(c), the strip remains stationary but the mouthpiece 13 is now pivotedso that the blister piercing member 15 pierces the lid of the previouslyaligned blister.

Although reference is made to a blister piercing member 15, it will beappreciated that multiple openings are formed in the lid of the blisterso that air can be drawn into the blister through one or some of thoseopenings and flow out of the blister together with an entrained dose ofmedicament, through one or more other openings and via the mouthpieceinto a patient's airway.

Once the actuating lever is in the position shown in FIG. 3(c), the usernow inhales through the mouthpiece 13, as shown by arrows indicated by“U” in FIG. 3(d).

After inhalation, the user rotates the cap in the opposite direction,i.e. in the direction indicated by “V” in FIG. 3(e). During thismovement, the cap 12 engages with the actuating lever 14 so that theactuating lever 14 also returns to its initial position as shown in FIG.3(a), the strip remaining stationary during this return movement of theactuating lever 14.

As mentioned above, the cap 12 is passive, although it does perform thefunction of re-setting the actuating member back to its originalposition in the event that the actuating lever is depressed prior toclosing the cap.

As previously mentioned, the inhaler has an indexing mechanism that haspreviously been described with reference to WO2009/092652 A1. Thisaspect of the inhaler of the invention will now be described in detailwith reference to FIGS. 8 to 13 a. Although the drawings show a slightlydifferent arrangement, in which an actuator 54 takes the place of adrive gear 16 attached to the drive coupling member 57 in the presentinvention, the principle remains the same as the actuator 54 and thedrive gear are both rotated to index the strip. Therefore, rotation ofthe drive gear 16 performs the same function as rotation of the actuator54 referred to in the description of FIGS. 8 to 13 a below.

Referring now to FIG. 8, there is shown a partial perspective view of aninhalation device 50 comprising an indexing mechanism 51.

The indexing mechanism 51 includes an indexing wheel 55 comprising fourvanes 55 a, 55 b, 55 c, 55 d, each having an enlarged head portion 56 a,56 b, 56 c, 56 d. As is clear from reference to FIGS. 1 and 2, once ablister strip (not shown in FIGS. 8 to 14) has passed over the blisterlocating chassis 53, it passes around the indexing wheel 55. A blisterlocates in the space between two vanes 55 a, 55 b, 55 c, 55 d so that,as the indexing wheel 55 rotates in response to rotation of the actuator54, a vane 55 a, 55 b, 55 c, 55 d engages a blister located between thevanes 55 a, 55 b, 55 c, 55 d so as to drive the strip around theindexing wheel 55 to sequentially move each blister forward by asufficient distance to move a fresh blister into alignment with ablister piercing element.

The indexing mechanism 51 includes a drive coupling member 57 (mostclearly shown in FIGS. 13a and 13b ) for selectively or temporarilycoupling the actuator 54 to the indexing wheel 55 so that, when coupled,the indexing wheel 55 rotates in response to rotation of the actuator 54to index the strip. The drive coupling member 57 comprises a shaft 58defining an axis of rotation “A” (see FIGS. 13a and 13b ) on which theindexing wheel 55 is rotatably received so that it can rotate freelyabout the shaft 58 about said axis of rotation “A”. The actuator 54 isfixedly attached to the drive coupling member 57 (the gear drive wouldalso be fixedly attached to the drive coupling member 57) so that thedrive coupling member 57 rotates together with the actuator 54 at alltimes. In the inhaler illustrated and described with reference to FIGS.8 to 12, the actuator 54, drive coupling member 57 and indexing wheel 55are all mounted coaxially for rotation about the same axis “A”. However,it will be appreciated that in the inhaler of FIG. 7, the mouthpiece 13and actuating lever 14 are not coaxially mounted with Axis ‘A’.

The drive coupling member 57 has a circular flange 59 that extendsradially from one end of the shaft 58. A portion 60 of the flange iscut-away (see arcuate opening 61 in FIG. 13a ) over an angle ofapproximately 180 degrees where the flange 59 joins the shaft 58 so thatthis portion 60 of the flange 59 is not directly attached to the shaft58 but only to the remaining portion of the flange 59 at each of itsends 60 a, 60 b. As a result, this portion 60 of the flange 59 isflexible relative to the rest of the flange 59 and can be deflected outof the plane of the flange 59 that extends at right angles to the axisof the shaft, in an axial direction (indicated by “T” and “S”, in FIG.13b ) either towards or away from the shaft 58 or, more importantly,towards or away from the indexing wheel 55 which is mounted on the shaft58, when force is applied to it. This flexible flange portion 60 hingesabout an axis B which intersects the axis A of the shaft 58 and actuator54 but extends at right angles to it. The drive coupling member 57, orat least the flange 59, is made from a resilient material so that whenthe deflected flexible flange portion 60 is released, it returns to itsneutral, unstressed position, in which it lies coplanar with theremaining fixed portion of the flange 59.

The flexible flange portion 60 has an integrally formed flangedeflecting dog 62 projecting radially from its circumferential edge. Theflange deflecting dog 62 has first and second angled engaging faces 63,64 on opposite sides. When the drive coupling member 57 is rotated inresponse to rotation of the actuator 54 in one direction, one of thefirst or second angled engaging faces 63, 64 cooperate with a fixedformation 65 on the housing 52 to cause the flexible flange portion 60to deflect in a first direction. When the drive coupling member 57 isrotated in the opposite direction, the other angled engaging facecooperates with the formation 65 on the housing 52 to cause the flexibleflange portion 60 to deflect in a second, opposite direction, as will beexplained in more detail below.

The flexible flange portion 60 also has an arcuately shaped indexingwheel drive dog 66 that upstands in an axial direction from its surfacetowards the indexing wheel 55 in the same direction as the shaft 58 andextends partially around the circumference of the flexible flangeportion 60. As will now be explained in more detail below, an end face66 a (see FIG. 13a ) of the indexing wheel drive dog 66 engages a vane55 a, 55 b, 55 c, 55 d of the indexing wheel 55 when the flexible flangeportion 60 has been deflected in a first direction, as indicated byarrow “T” in FIG. 13b (the flange portion 60 is shown in its deflectedposition in FIG. 13b ), so that the indexing wheel 55 is driven togetherwith the drive coupling member 57.

As mentioned above, the flange deflecting dog 62 engages a formation 65on the housing 52 when the drive coupling member rotates in response torotation of the actuator 54 so as to flex the deflectable portion 60 ofthe flange 59. This formation 65 comprises first and second arcuatelyshaped tracks or paths 67, 68 positioned one above the other or spacedfrom each other in the axial direction. The surface of the innermosttrack 67 is visible in FIG. 8. The lower or outermost track 68 islocated beneath it and is visible in FIG. 12. The ends of the tracks 67a, 68 a have angled faces for reasons that will become apparent.

When the actuator 54 (or the drive gear) is rotated in a firstdirection, the drive coupling member 57 rotates together with it and thefirst outwardly facing angled surface 63 on the flange deflecting dog 62contacts the angled face 67 a of the innermost track 67. Furtherrotation of the drive coupling member 57 causes the flange deflectingdog 62 to ride up onto the surface of the innermost track 67 therebydeflecting the flexible flange portion 60 inwardly, i.e. in a directioninto the housing 52 or towards the shaft 58 and the indexing wheel 55.

When the flexible flange portion 60 has been deflected inwardly in thedirection of arrow T, further rotation of the drive coupling member 57causes the indexing wheel drive dog 66 to engage a vane, which as shownin FIG. 8 is vane 55 c, of the indexing wheel 55 so that the indexingwheel 55 rotates together with the drive coupling member 57 and drive tothe indexing wheel 55 is engaged.

When the end of the innermost track 67 has been reached, the flangedeflecting dog 62 falls off the surface of the track 67 and theresilience of the flexible flange portion 60 causes it to return to itsoriginal unstressed or neutral position. When the drive coupling member57 is rotated further, the indexing wheel drive dog 66 no longer engageswith the vane 55 c of the indexing wheel 55 and instead passes beneathit so the indexing wheel 55 remains stationary. Therefore, drive to theindexing wheel 55 is disengaged, despite continued rotation of theactuator 54 in the same direction.

When the actuator 54 is rotated back in the opposite direction towardsits home position, the second inwardly facing angled surface 64 of theflange deflecting dog 62 now contacts the lower or outermost track 68 sothat the flange deflecting dog 62 now rides onto the surface of thatsecond track 68, thereby causing the flexible flange portion 60 todeflect outwardly or in the opposite direction to the direction in whichit was previously deflected. Engagement of the flange deflecting dog 62with the outermost track 68 so as to deflect the flange portion 60 inthe opposite direction, enables the drive coupling member 57 to rotatein the opposite direction without any drive to the indexing wheel 55.

It will be appreciated that, if the flange portion 60 was not deflectedin the opposite direction, the flange deflecting dog 62 would simplyengage against the end of the formation 65 in the housing 52 whenrotated back in the opposite direction, thereby preventing rotation inthe opposite direction or, the flange deflecting dog 62 would travelback over the innermost track 67 deflecting the flexible flange portion60 in the same direction causing the opposite end 66 b of the indexingwheel drive dog 66 to engage with a vane 65 b of the indexing wheel 65thereby driving the indexing wheel 65 backwards rather than leaving itstationary with no drive engaged. Therefore, it is necessary to ensurethat the flexible flange portion 60 is deflected in the oppositedirection so that there is no drive to the indexing wheel duringrotation of the coupling member 67 in the opposite direction.

When the flange deflecting dog 62 reaches the end of the outermost track68, the flexible flange portion 60 returns to its original unstressed orneutral position, due to its resilience.

It will be appreciated that the extent of rotation of the indexing wheel55 relative to the extent of rotation of the actuator 54 may becontrolled by altering the circumferential length of the inner and outertracks 67, 68. If the tracks are made longer, the flexible flangeportion 60 will be deflected for a greater proportion of the anglethrough which the actuator 54 is rotated and so the indexing wheel drivedog 66 will be engaged with the indexing wheel 55 to rotate the indexingwheel 55 throughout that angle. If required, the tracks 67, 68 could bemade sufficiently long so that the indexing wheel 55 rotates duringrotation of the actuator 54 through its entire angle of movement in onedirection. Alternatively, the tracks 67, 68 could be made shorter toreduce the angle through which the actuator 54 and indexing wheel 55rotate together. Ideally, the track length can be selected so that theindexing wheel 55 is rotated through a sufficient angle to move thenext, unused blister, into alignment with the blister piercing element.

The further rotation of the actuator 54 (the gear drive) causes themouthpiece to rotate so that the blister piercing member pierces the lidof a blister that has just been moved into alignment with the blisterpiercing element.

It will be appreciated that the indexing mechanism 51 is designed toenable a stroke to be aborted when the actuator 54 or cap has beenrotated through an angle which is sufficient to cause initial indexingof the strip but which is not such that the drive to the indexing wheel55 has disengaged, i.e. a position in which the flange deflecting dog 62has not reached the end of the innermost track 67. If the stroke isaborted and the actuator 54 returned to its original position beforedrive to the indexing wheel 55 has disengaged (or the drive gear rotatedback to its initial position), the strip will be driven backwards intoits original position as a rear surface 66 b of the indexing wheel drivedog 66 will engage a preceding vane 55 b to drive the indexing wheel 55in the opposite direction.

The indexing mechanism 51 also includes optional means for locking theindexing wheel 55 to prevent its rotation between indexing steps andmeans for temporarily releasing that lock to allow rotation of theindexing wheel 55 when driven by the indexing wheel drive dog 66. Thelock also improves positional accuracy of the strip and, morespecifically, the next blister to be pierced. This locking arrangementwill now be described in more detail below, although it should be notedthat the locking mechanism can be omitted altogether.

The blister location chassis 53 may optionally comprise a resilientlyflexible cantilever arm 70 that extends from the body 53 of the chassistowards the indexing wheel 55. The free end of the cantilever arm 70 hasan enlarged head portion 71 comprising a letterbox shaped slot, windowor opening 72 in which the head 56 c of a vane 55 c of the indexingwheel 55 is located. The opening 72 is dimensioned such that the head 56c of the vane 55 c (as shown in FIG. 8) is a snug fit therein so thatrotation of the indexing wheel 55 is prevented. In the normal or homeposition of the actuator 54, the head 56 c of a vane 55 c is located insaid opening 72 in the cantilever arm 70 of the chassis 53 so thatrotation of the indexing wheel 55 is prevented.

When the actuator 54 is rotated and the flange deflecting dog 62 engagesthe innermost track 67 so as to deflect the flexible portion of theflange 60 inwardly towards the indexing wheel 55, the indexing wheeldrive dog 66 initially engages with a protrusion 71 a extending from aninner side of the enlarged head 71 on the cantilever arm 70 of thechassis 53 so that the cantilever arm 70 is deflected outwardly, awayfrom the indexing wheel 55, to free the head 56 c of the vane 55 c fromthe slot 72, thereby unlocking the indexing wheel 55. Only once theindexing wheel 55 has been released by the indexing wheel drive dog 66pushing the cantilever arm 70 away from the indexing wheel 55 does theindexing wheel drive dog 66 subsequently engage a vane 55 c of theindexing wheel 55 so that further rotation of the drive coupling member57 rotates the indexing wheel 55.

Prior to the flange deflecting dog 62 falling off the end of theinnermost track 67 and the flexible flange portion 60 returning to itsundeflected state due to its resilience, the indexing wheel drive dog 66no longer pushes against the cantilever arm 70 and so the cantilever arm70 is free to move back towards the indexing wheel 55. As the cantileverarm 70 is free to move back just prior to rotation of the indexing wheel55 being completed, the cantilever arm is prevented from moving all theway back by the head 56 b of a following vane 55 b which contacts thecantilever arm 70. During further rotation of the indexing wheel, thehead 56 b slides across the cantilever arm and then drops into theopening 72 thereby allowing the cantilever arm 70 to move all the wayback and locking the indexing wheel 55 in position prior to any furtherrotation of the drive coupling member 57 in response to continuedrotation of the actuator 54.

On the return stroke of the actuator 54, it will be appreciated thatdeflection of the flexible flange portion 60 in the opposite direction,i.e. in a direction away from the indexing wheel, also ensures that theindexing wheel drive dog 66 clears the chassis arm 70 and so theindexing wheel 55 is not unlocked, thereby preventing any rotation ofthe indexing wheel 55 during the return stroke.

The blister strip drive member or indexing wheel may take a slightlydifferent form to that described with reference to FIGS. 8 to 13 b,although the principle still remains the same. In particular, theindexing wheel 17 may be used to squeeze the used blister cavities asthey pass around it, thereby at least partially crushing them. This isachieved by enlarging the axle or hub 18 of the indexing wheel so thatthe distance (X in FIG. 14) between the hub and the casing or wall ofthe device 11, or a component fixed to the casing 11, is less than themaximum height of a blister cavity. As the blister cavities areentrained between the spokes 17 a of the indexing wheel 17, onwardrotation of the wheel 17 causes the cavities to be at least partiallysquashed or sandwiched between the enlarged hub 18 of the indexing wheel17 and the casing 11 of the device. The advantage of at least partiallycrushing the empty blister cavities is that they then take up less spacewhen coiled within the used blister chamber of the device as the coiledstrip has a smaller diameter. Furthermore, a natural curvature isimparted to the strip, both as a result of being fed around the blisterdrive wheel and also as a result of the crushing of the blistercavities. This encourages the used portion of the strip to coil morereadily. It is also apparent that, when the blister cavities have beencrushed, the cavity is more resilient to denting at the point at whichthe spoke of the blister drive wheel contacts the strip, i.e. at theroot where the blister cavity meets the remainder of the strip.Therefore, a more positive and precise drive of the strip is achievedwhen the blisters have been crushed.

As mentioned above, the drive coupling member 57 of the inhaler of thepresent invention is modified in that the drive gear 16 is attachedthereto in place of the actuator 54 so that the drive coupling member 57rotates in response to rotation of the drive gear 16. It is alsoenvisaged that the drive gear 16 may be moulded integrally with thedrive coupling member 57.

It will be apparent from FIG. 7, that the drive coupling member 57extends into an opening 19 in a side wall of the shell 11 b of thehousing 11 and the drive gear 16 is coupled thereto so that it isdisposed on the outside surface of said side wall, only the drivecoupling member 57, the blister strip drive wheel 17 and the blisterstrip itself, being received within the housing between the shellportions 11 a, 11 b.

The actuating lever 14 has a first plate-like portion 20 that extendsacross the outside surface of the shell 11 b and has a hole 21 thereinto receive a boss 22 upstanding from said surface, to pivotally mountthe actuating lever 14 to the shell 11 for rotation about a second axis(A-A in FIGS. 7 and 15). The actuating lever 14 may also have a secondplate-like portion 23 that is parallel to and spaced from the firstportion 20 by an actuating button 24. The second plate-like portionextends across the opposite surface of the shell 11 a and also has ahole 25 to engage with a corresponding boss upstanding from saidopposite surface so as to pivotally couple the actuating member 14 tothe shell 11 with the actuating button extending between the plates 20,23 and opposite surfaces of the shell portions 11 a, 11 b.

The first plate 20 has a further aperture 26 therein and the cap 12 ispivotally mounted to the outer shell portion 11 b by a coupling such asa boss 80 upstanding from a surface of the shell portion 11 b thatlocates in a corresponding recess (not shown in FIG. 7, but see hole 92in FIG. 15) in the cap 12, for rotation of the cap 12 about a thirdaxis. The boss 80 extends through the aperture 26 in the actuatingmember 14. The aperture 26 is arcuately-shaped and has the second axisas its centre so that, when the actuating lever 14 is rotated about thesecond axis, the boss 80 travels within the aperture 26 without engagingthe actuating member 14, and so the cap 12 remains stationary. Theactuately-shaped aperture 26 acts as a clearance hole for the pivotalattachment of the cap 12 to the shell 11 b and so as to allow rotationof the actuating lever 14 about the second axis.

A drive member (not shown) extends from an inner surface of the cap 12.The drive member is located between, and spaced from, each of the secondand third axes and extends towards the actuating lever 14 and theactuating lever 14 includes a wall 27 for engagement by said drivemember when the cap 12 is rotated it about its third axis back towardsits closed position and after the actuating member 14 has been rotatedabout its second axis. The drive member and wall 27 meet at a locationbetween the second and third axes so that, upon further rotation of thecap 12 back towards its closed position, the drive member pushes againstthe wall 27. Pressure of the drive member against the wall 27 causes theactuating member 14 to rotate back into its original position, togetherwith the cap 12 into its closed position.

The cap 12 and actuating lever 14 are configured so that, when the cap12 is in its closed position and the actuating lever 14 has returned toits initial position, the cap 12 overlies the actuating button 24 whichis pressed by a user to operate the device. This prevents a user fromattempting to operate the device by rotating the actuating member 14prior to opening the cap 12.

The actuating member 14 has a gear segment, toothed region or element 28that drivingly meshes with the gear drive 16 so that rotation of theactuating member 14 also causes rotation of the gear drive 16 andselective rotation of the blister strip drive member relative to thegear drive 16 whilst the actuating member 14 is rotated through theinitial portion of its stroke, due to the indexing mechanism describedabove, so that the blister strip is initially driven to move the nextblister into alignment with the blister piercing member 15. Duringfurther rotation of the actuating member 14 through the second portionof its stroke, the blister strip is prevented from moving as the drivecoupling member 57 is de-coupled from the blister strip drive wheel 17.During rotation through the second portion of its stroke, the blisterpiercing member 15 carried by the mouthpiece 13 is rotated so that itpierces the aligned, and now stationary, blister.

A drive cam element 32 (not shown in FIG. 7, but shown in FIG. 15)extends from the first plate 20 towards the second plate 23. The drivecam element 32 is received in a cam groove or slot 29 formed in aperipheral wall 30 depending from the mouthpiece 13. As is apparent fromFIG. 7, the cam groove or slot 29 has an arcuate portion 29 a followedby a leg portion 29 b at one end. It will be appreciated that the slot29 may alternatively be provided in the actuating lever 14 and the drivecam element 32 may extend from the mouthpiece 13 to achieve the samefunction.

During initial rotation of the actuating member 14 through the firstportion of its stroke, the drive cam element 32 slides along the arcuateportion 29 of the cam slot 29 without causing any movement of themouthpiece 13, as the arcuate portion 29 a of the cam slot 29 has thesecond axis as its radius. However, during subsequent rotation of theactuating member 14, the cam member reaches the leg portion 29 b of thecam slot 29 and engages the side walls of the cam groove 29 so as tocause the mouthpiece 13 to rotate about a first axis B-B together withthe actuating member 14 thereby pulling the blister piercing member 15,depending from the mouthpiece 13, into the aligned blister.

Although reference is made to a pivoting mouthpiece 13, it will also beappreciated that, in an alternative embodiment, the blister piercingmember 15 may be pivotally attached to a mouthpiece 13 or mounted in asupport or module that is pivotally attached to the mouthpiece 13. Inthese embodiments, the mouthpiece 13 itself remains stationary so that,in response to operation of the actuating member 14, the blisterpiercing member 15 pivots relative to the stationary mouthpiece 13 topuncture the lid of an aligned blister.

During rotation of the cap 12 from its open to its closed position,rotation of the actuating member 14 due to rotation of the cap 12 alsocauses rotation of the mouthpiece back to its original position as thecam member travels back along the cam slot 29 b.

As shown in FIG. 7, a spiral element 31 is also optionally mountedwithin the housing 11 into which the used portion of the strip is fed.

Although a region is provided within the housing 11 to receive the usedportion of the strip, it will be appreciated that the invention is alsoapplicable to other inhalation devices (not shown) in which usedblisters are not retained within the housing 11 but pass out through anopening (not shown) in the wall of the housing 11 for periodicdetachment by a user.

Although piercing of an aligned blister only occurs after movement ofthe strip has stopped, it is envisaged that the mechanism could beconfigured so that de-coupling of the blister strip drive wheel 17 andthe drive coupling member 57 only occurs after the blister piercingmember 15 has pierced, or begun to pierce, the lid of a blister so thatthe piercing element is drawn across and through the lid of the blisteras it enters it. This creates a larger hole relative to the size of thehole created when the strip is stationary prior to being puncturing bythe blister piercing element. A larger hole can advantageously ensurethat all the drug dose is entrained and removed from the blister.

A modified embodiment is shown in FIGS. 15 and 16. This embodiment issimilar to the previous embodiment and functions in the same way butadditionally includes a detent mechanism for holding the actuating lever81 at the end of its stroke so that a small force must be applied to itto overcome the hold placed on it by the detent mechanism and allow theactuating lever 81 to return to its initial position. The detentmechanism includes a cantilever 82 that extends from the actuating lever81 and has a kinked region 82 a which engages with a pawl 83 on theshell portion 84 b as the actuating lever 81 approaches the end of thesecond portion of its stroke, so that the cantilever 82 is resilientlydeformed and as it rides over the kinked region 82 a and springs back toits original shape once the pawl 83 has cleared the kinked region 82 a.When the actuating lever 81 is rotated back towards its initialposition, sufficient force must initially be applied to the actuatinglever 81 so that the cantilever 82 is deformed by the pawl 83 and ridesback over it. In addition to providing a slight resistance to initialmovement of the actuating lever 81, it also generates an audible ‘click’as the end of the second portion of the stroke of the actuating lever 81is reached and so provides an audible signal to the user that the end ofthe travel of the actuating lever 81 has been reached.

This embodiment also includes a rigid dividing wall 85 that separatesthe interior of the housing into an unused and used blister chamber 86,87 (see FIG. 16). The wall 85 is slideably mounted within the shellportion 84 a of the housing so that, as more of the blisters are used,the force of the used coil of blisters in the used blister chamber 86presses against the wall 85 and pushes it in the direction indicated byarrow ‘P’ in FIG. 16, to enlarge the space for the used blisters andreduce the space previously occupied by the unused blisters.

The sliding wall 85 comprises an elongate foot 88 which is attached toand integrally formed with a baffle 89 that divides the compartment. Anapproximate central region 88 a of the foot 88 is attached to the baffle89 so that it extends in opposite directions on either side of thebaffle 89. The foot 88 is slideably received in a recess 90 formed in awall of the housing and is wider at its ends 88 b than in its centre 88a where it joins the baffle 89 so that contact with the walls of therecess 90 is primarily made with the wider ends 88 b of the foot 88.

A deeper, narrower recess 91 may extend deeper into the wall within thefirst recess 90 to receive a strengthening rib (not shown) dependingfrom the underside of the foot 88.

As indicated above, the blister strip drive wheel 17 is rotatablymounted in the chamber to sequentially move each blister into a positionin which it can be opened, preferably using a blister piercing elementthat punctures the lid of an aligned blister. However, the drive gear16, which is driven to rotate the blister strip drive wheel 17, isdisposed on the outside of the housing remote from the chamber in whichthe blister strip and blister strip drive wheel 17 are received.Similarly, the actuating lever 14 is disposed on the outside of thehousing and is remote from the chamber. The drive gear segment orelement 28 on the actuating lever 14 is therefore also on the outside ofthe housing, remote from the chamber. This has the advantage that anyloose powder dose contained in the chamber is substantially preventedfrom contacting the gear segment 28 and the drive gear 16, which couldincrease friction and be deterimental to satisfactory blister indexing.

The respective drive gears namely, the drive gear 16 and the gearsegment 28, are disposed between the housing 11 and the cap 12 so as tobe enclosed by said cap 12 which includes portions 12 a, 12 b thatextend across respective side wall surfaces of the housing 11. Thismeans that the drive gear 16 and the gear segment 28 are disposedbetween one of said side wall surfaces and one of said cap portions 12a, 12 b.

The drive gear 16 is connected to the blister strip drive wheel 17, viathe drive coupling member 57, through the aperture 19 in the side wallof the housing.

It will also be appreciated that the mouthpiece is mounted to theoutside of the housing, said peripheral wall 30 extending from opposingedges extending across respective side wall surfaces on the outside ofthe housing remote from the chamber. The peripheral walls are pivotallymounted to the side wall surfaces of the housing and are covered by aportion 12 a of the cap 12.

A further inhaler will now be described with reference to FIGS. 17a to17f . The inhaler of FIGS. 17a to 17d is additionally provided with ashutter 100 (see FIGS. 17e and 17t ) that blocks the mouthpiece 13 whenthe mouthpiece 13 is in its raised position, but which pivots as themouthpiece 13 is pulled downwardly in response to pressure on theactuating lever 14, 81 to pierce a blister so that the mouthpiece 13 isopened to allow a dose to pass therethrough when a patient inhales.

A top perspective view of the inhaler according to this embodiment canbe seen in FIG. 17a . A corresponding side elevational view is shown inFIG. 17b , but with the cap 12 removed for clarity. In FIG. 17a , thecap 12 has been pivoted into its open position but the actuating lever14, 81 has not yet been activated. As is visible in FIG. 17a , themouthpiece 13 is blocked by a shutter portion 101 of a shutter component100 which is visible through the mouthpiece opening 13 a.

A top perspective view of the inhaler can also be seen in FIG. 17c ,together with a corresponding side view in FIG. 17d (with the cap 12removed for clarity). However, in these views, the actuating lever 14,81 has been pivoted through the full extent of its stroke so that themouthpiece 13 has been driven downwardly and rotated about its pivot‘B’.

With reference to FIGS. 17b and 17d , it will be appreciated that theshutter 100 is represented in dashed lines to indicate that it ispositioned beneath the mouthpiece 13 so that it is situated between themouthpiece 13 and the casework 11, and so only part of the shutterportion 101 is visible to a user through the mouthpiece opening 13 a.

The shutter portion 101 extends from one end of a pivot arm 102 and isarcuate in shape. A first section 101 a of the arcuate shutter portion101, extending directly from the pivot arm 102, is solid so that itcompletely blocks the mouthpiece opening 13 a, whereas a second section101 b of the shutter portion 101 that extends from the first section 101a, remote from the pivot arm 102 is provided with openings 103, thatform a mesh for the passage of an entrained dose out of the mouthpiece13 and into the patient's mouth, although it is envisaged that aseparate, stationary mesh, could be formed integrally with themouthpiece 13 below the first section 101 a, in which case the secondportion 101 b of the shutter arm 101 is not required.

The opposite end 104 of the pivot arm 102, remote from the shutterportion 101, is pivotally mounted to the mouthpiece 13 for rotationabout an axis ‘X’. The end 104 has an enlarged region relative to therest of the pivot arm 102 and which extends laterally from the pivotaxis ‘X’. A cam slot 105 is formed in the enlarged region to receive afixed cam pin 106 upstanding from the casework 11. The cam pin 106 isfree to slide within the slot 105.

The arrangement is such that, as the mouthpiece 13 rotates about itspivot axis ‘B’ in response to pressure applied to the actuating lever14, 81, the shutter 100 also rotates about its axis ‘X’ due to theinteraction between the fixed cam pin 106 and the cam slot 105. Theshutter 100 is thereby rotated into its position shown in FIGS. 17c and17d , in which the second portion 101 b of the shutter portion 101 isaligned with the mouthpiece opening 13 a to allow passage of anentrained dose through the mouthpiece opening 13 a.

The shutter 100 rotates in the opposite direction when the mouthpiece 13pivots back to its original position in response to the cap 12 beingclosed (due to rotation of the mouthpiece 13 in the opposite directionas driven by the cap 12), thereby moving the first shutter portion 101back into the mouthpiece opening 13 a and blocking the mouthpiece 13.

Once the shutter is no longer visible through the mouthpiece opening 13a, the dose is pierced and ready to be inhaled. The shutter 100 alsoprovides further protection to the mouthpiece (in addition to the cap12) against the ingress of dust or debris into the inhaler which mayoccur if, for example, the cap 12 was pivoted into its open position andthe inhaler was left in this state, with the mouthpiece 13 revealed,prior to depression of the actuating lever 14, 81 to pierce an alignedblister.

As the shutter 100 is pivotally mounted to the mouthpiece 13 and not tothe casework 11, the shutter portions 101 a, 101 b always retain thesame distance to the mouthpiece opening irrespective of the rotationaldisplacement of the mouthpiece 13 so that the arcuate shutter portionsalways remain in the same close clearance to corresponding surfaces onthe mouthpiece 13.

Embodiments of the present invention are concerned with a modificationto the detent mechanism that will now be described with reference toFIG. 18. FIG. 18a shows cross-section of an inhaler according to theinvention with the actuating lever 81 in its initial position and FIG.18b shows the same view but after the actuating lever 81 has beenrotated into its piercing position. It will be appreciated that, in thedetent mechanism described above, the cantilever 82 is relaxedthroughout its stroke until just before the actuating lever 81 reachesthe end of its stroke, so that a small force must be applied to the capit to overcome the hold placed on it by the detent mechanism and allowthe actuating lever 81 to return to its initial position. In themodified arrangement that forms an embodiment of the present invention,the cantilever 82 runs up a ramp 300 during rotation of the actuatinglever 81 from its initial position to its fully depressed position sothat a biasing force is applied to the cantilever 82 throughout all, orat least a substantial portion of, the stroke of the actuating lever 81.

The shape of the ramp 300 is designed so that the degree of deflectionof the cantilever 82 changes depending on the tactile effect that isrequired and so that, for example, a user experiences the same feel oris required to apply the same level of force to the actuating lever 81throughout its entire stroke. This is because, as the degree ofdeflection of the cantilever 82 changes along with a change in the rateof deflection, caused by a change in the slope of the ramp 300, theamount of pressure that must be applied to the actuating lever 81 alsochanges. Thus, the pressure that must be applied to the actuating lever81 to overcome the biasing force applied to the cantilever 82 in orderto cause the actuating lever to rotate can be altered or increased. Morespecifically, the ramp 300 may be tuned so that the peak level ofloading that would otherwise have to be applied to the actuating lever81 is felt throughout the entire movement of the actuating lever 81, asopposed to just at a particular point during its stroke. For example,the highest load level may be felt when the drive cam element reachesthe end of the arcuate cam surface and as the mouthpiece/blisterpiercing member begins to rotate so as to force the blister piercingelement into the lid of an aligned blister. Therefore, by shaping theramp 300 so that the biasing force applied to the cantilever 82 isrelatively high during movement of the actuating lever 81 up until thepoint at which the drive cam element reaches the end of the arcuate camsurface, and so that the load applied to the cantilever by the ramp 300is removed or reduced beyond this point, the feel or feedback providedto the user can be optimised. As shown in FIG. 18, the ramp 300 may beshaped so that the biasing force that has built up in the cantilever 82is gradually released at the end of the stroke of the actuating lever.The release of the load on the cantilever has the effect of pulling theactuating lever through its final few degrees of rotation into its finalfully actuated position. As the patient is provided with a consistent orother advantageous feel or user feedback throughout the entire stroke ofthe actuating lever 81, this may prevent them from thinking they havereached the end of the stroke of the actuating lever 82 too soon, justas a result of feeling a slightly greater resistance to movement at thepoint at which the mouthpiece or blister piercing element begins torotate. The shape of the ramp 300 can therefore be shaped to mask pointsat which the load applied to the actuating lever 81 changes or to assisttravel of the actuating lever 81.

Many modifications and variations of the invention falling within theterms of the following claims will be apparent to those skilled in theart and the foregoing description should be regarded as a description ofthe preferred embodiments of the invention only. For example, althoughreference is made to a “mouthpiece”, the invention is also applicable todevices in which the dose is inhaled through the nasal passages.Therefore, for the purposes of this specification, the term “mouthpiece”should also be construed so as to include within its scope a tube whichis inserted into the nasal passages of a patient for inhalationtherethrough.

Furthermore, although the blister piercing member 15 is described asbeing attached to the mouthpiece so that the mouthpiece 13 and theblister piercing member rotate together, it is also envisaged that themouthpiece itself could remain stationary and the blister piercingmember 15 could be pivotally mounted to the mouthpiece 13 so that theblister piercing member 15 rotates relative to the mouthpiece 13 topierce the lid of an aligned blister.

In another embodiment, the cap and the actuating member could becombined into a single component so that rotation of the cap also causesindexing of the strip and piercing of an aligned blister.

It will be appreciated that the inhaler of the invention may be either apassive or active device. In a passive device, the dose is entrained ina flow of air caused when the user inhales through the mouthpiece.However, in an active device, the inhaler would include means forgenerating a pressurised flow of gas or air through the blister toentrain the dose and carry it out of the blister through the mouthpieceand into the user's airway. In one embodiment, the inhaler may beprovided with a source of pressurised gas or air within the housing.

The invention claimed is:
 1. An inhaler comprising a housing to receivea strip having a plurality of blisters, each blister having apuncturable lid and containing a dose of medicament for inhalation by auser, a mouthpiece mounted to the housing and through which a dose ofmedicament is inhaled by a user, a blister piercing member mounted forrotation about a first axis and an actuating mechanism including anactuating lever mounted for rotation about a second axis to sequentiallymove each blister into alignment with the blister piercing member,wherein the actuating lever cooperates with the blister piercing memberso that the blister piercing member pivots about said first axis inresponse to rotation of the actuating lever from an initial positionabout the second axis to puncture the lid of an aligned blister so anairflow through the blister is generated to entrain the dose containedtherein and carry it, via the mouthpiece, into the user's airway when auser inhales through the mouthpiece, wherein the inhaler furthercomprising an actuating lever load control member to control the forcethat must be applied to the actuating lever to cause it to rotate fromthe initial position such that a biasing force is applied to theactuating lever throughout all, or at least a substantial portion of,the stroke of the actuating lever, the load control member comprising acantilever on the actuating lever and a ramp on the housing, said rampbeing shaped to change the degree of deflection of the cantilever duringthe stroke of the actuating lever, wherein the ramp is shaped such thatthe load applied to the cantilever gradually increases until the blisterpiercing member begins to pivot about said first axis.
 2. An inhaleraccording to claim 1, wherein the ramp is shaped so that the loadapplied to the cantilever is gradually released, the force of thecantilever against the ramp urging the actuating lever into a fullyactuated position.
 3. An inhaler according to claim 1, wherein theblister piercing member is immovably attached to the mouthpiece and themouthpiece is pivotally mounted to the housing so that the mouthpiecepivots, together with the blister piercing member, about said first axisin response to rotation of the actuating lever about the second axis. 4.An inhaler according to claim 1, wherein the blister piercing member ispivotally mounted to the mouthpiece for rotation about said first axisso that the blister piercing member pivots about said first axisrelative to the mouthpiece, in response to operation of the actuatinglever.
 5. An inhaler according to claim 1, wherein the actuating leveris pivotable in the same direction about the second axis to sequentiallymove each blister into alignment with the blister piercing member and tocause rotation of the blister piercing member about the first axis sothat the blister piercing member punctures the lid of an alignedblister.
 6. An inhaler according to claim 5, wherein the actuatingmechanism is configured such that rotation of the actuating lever aboutthe second axis through a first portion of its stroke moves the blisterinto alignment with a blister piercing member and, further rotation ofthe actuating lever about the second axis in the same direction, duringa second portion of its stroke, causes rotation of the blister piercingmember about the first axis so that the blister piercing memberpunctures the lid of an aligned blister.
 7. An inhaler according toclaim 6, wherein the actuating mechanism includes a blister strip drivewheel, wherein the actuating lever is engaged with said blister stripdrive wheel during rotation of the actuating lever to rotate saidblister strip drive wheel and drive said strip.
 8. An inhaler accordingto claim 7, wherein the blister strip drive wheel comprises a pluralityof spokes extending from a hub, the spokes being spaced from each othersuch that one of the plurality of spokes is located between blistercavities as a blister strip passes around the blister strip drive wheelto engage and drive a strip as the blister strip drive wheel rotates,the blister strip drive wheel being positioned relative to a wall suchthat the distance between the hub and said wall is less than the heightof the blister cavity such that onward rotation of the wheel causes theblister cavity to be at least partially squashed or sandwiched betweenthe hub and said wall.
 9. An inhaler according to claim 7, wherein theactuating mechanism is configured such that the actuating lever andblister strip drive wheel disengage at the end of the first portion ofthe stroke so that the blister strip drive wheel remains substantiallystationary during rotation of the actuating lever through said secondportion of its stroke.
 10. An inhaler according to claim 9, wherein theactuating mechanism comprises a drive coupling member rotatable inresponse to rotation of the actuating lever to rotate the blister stripdrive wheel, the blister strip drive wheel being rotatably mounted onsaid drive coupling member, wherein the actuating mechanism includesmeans to control rotation of the blister strip drive wheel relative torotation of the drive coupling member so that the blister strip drivewheel rotates together with the drive coupling member during the firstportion of the stroke of the actuating lever but not during the secondportion of the stroke of the actuating lever.
 11. An inhaler accordingto claim 10, wherein said means for controlling rotation of the blisterstrip drive wheel is also configured to inhibit rotation of the blisterstrip drive wheel when the actuating lever is rotated in the oppositedirection.
 12. An inhaler according to claim 10, wherein the means tocontrol rotation of the blister strip drive wheel includes cooperatingelements on the drive coupling member and on the housing.
 13. An inhaleraccording to claim 10, wherein the drive coupling member includes adrive gear rotatable together with the drive coupling member and theactuating lever includes a drive gear segment that drivingly engageswith the drive gear so that the drive gear rotates in response torotation of the actuating lever to rotate the drive coupling member. 14.An inhaler according to claim 1, wherein one of the actuating lever andthe mouthpiece has a drive cam element and the other of the actuatinglever and the mouthpiece has a drive cam surface, wherein the drive camelement cooperates with the drive cam surface so that the mouthpiecepivots about said first axis in response to rotation of the actuatinglever about the second axis to puncture the lid of an aligned blister,wherein the actuating lever is pivotable in the same direction about thesecond axis to sequentially move each blister into alignment with theblister piercing member and to cause rotation of the blister piercingmember about the first axis so that the blister piercing memberpunctures the lid of an aligned blister and wherein the blister piercingmember is immovably attached to the mouthpiece and the mouthpiece ispivotally mounted to the housing so that the mouthpiece pivots, togetherwith the blister piercing member, about said first axis in response torotation of the actuating lever about the second axis.
 15. An inhaleraccording to claim 14, wherein the drive cam surface includes a camgroove, the cam groove having an arcuately shaped region having an axisthat corresponds to the second axis about which the actuating leverrotates such that, during said initial rotation of the actuating leverthrough its first portion of its stroke, the drive cam element slidesalong said arcuately shaped region of the cam groove without causingrotation of the mouthpiece about the first axis.
 16. An inhaleraccording to claim 15, wherein the cam groove has a second region shapedsuch that, during further rotation of the actuating lever through itssecond portion of its stroke, cooperation between the drive cam elementand the second region of the cam groove causes the mouthpiece to rotatetogether with the actuating lever so that the blister piercing memberpunctures the lid of an aligned blister.
 17. An inhaler according toclaim 1, wherein one of the actuating lever and the blister piercingmember has a drive cam element and the other of the actuating lever andthe blister piercing member has a drive cam surface, wherein the drivecam element cooperates with the drive cam surface so that the blisterpiercing member pivots about said first axis in response to rotation ofthe actuating lever about the second axis to puncture the lid of analigned blister, wherein the blister piercing member is pivotallymounted to the mouthpiece for rotation about said first axis so that theblister piercing member pivots about said first axis relative to themouthpiece, in response to operation of the actuating lever and whereinthe actuating lever is pivotable in the same direction about the secondaxis to sequentially move each blister into alignment with the blisterpiercing member and to cause rotation of the blister piercing memberabout the first axis so that the blister piercing member punctures thelid of an aligned blister.
 18. An inhaler according to claim 17, whereinthe drive cam surface includes a cam groove, the cam groove having anarcuately shaped region having an axis that corresponds to the secondaxis about which the actuating lever rotates such that, during saidinitial rotation of the actuating lever through its first portion of itsstroke, the drive cam element slides along said arcuately shaped regionof the cam groove without causing rotation of the blister piercingmember about the first axis.
 19. An inhaler according to claim 18,wherein the cam groove has a second region shaped such that, duringfurther rotation of the actuating lever through its second portion ofits stroke, cooperation between the drive cam element and the secondregion of the cam groove causes the blister piercing member to rotatetogether with the actuating lever so that the blister piercing memberpunctures the lid of an aligned blister.
 20. An inhaler according toclaim 1, comprising a cap and a coupling pivotally mounting the cap tothe housing for rotation about a third axis, the cap covering themouthpiece in a closed position.
 21. An inhaler according to claim 20,wherein the housing comprises a shell and the actuating lever is mountedfor rotation about the second axis on the shell and includes a mountingplate that extends within a space between the shell and the cap.
 22. Aninhaler according to claim 21, wherein the actuating lever comprises abutton extending from said plate and protruding out of said space toenable actuation of the actuating lever by a user.
 23. An inhaleraccording to claim 21, wherein the actuating lever comprises anarcuately shaped opening extending about the second axis, the couplingthat pivotally mounts the cap to the housing extending through saidopening so that the coupling travels along the arcuately shaped openingas the actuating lever pivots about the second axis.
 24. An inhaleraccording to claim 23, wherein the cap and actuating lever includecooperating means configured such that, when the cap is rotated from itsopen position back into its closed position in which it covers themouthpiece, the actuating lever is rotated rotate back into its initialposition.